fix #288 (#289)

Author: antonmos

src/main/java/com/launchdarkly/sdk/server/integrations/FileDataSourceParsing.java

@@ -10,7 +10,9 @@
 import com.launchdarkly.sdk.server.subsystems.DataStoreTypes.ItemDescriptor;
 
 import org.yaml.snakeyaml.Yaml;
+import org.yaml.snakeyaml.constructor.SafeConstructor;
 import org.yaml.snakeyaml.error.YAMLException;
+import org.yaml.snakeyaml.representer.Representer;
 
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
@@ -149,7 +151,7 @@ public FlagFileRep parseJson(JsonElement tree) throws FileDataException, IOExcep
  * </ul>
  */
  static final class YamlFlagFileParser extends FlagFileParser {
- private static final Yaml yaml = new Yaml();
+ private static final Yaml yaml = new Yaml(new SafeConstructor(), new Representer());
  private static final Gson gson = new Gson();
  private static final JsonFlagFileParser jsonFileParser = new JsonFlagFileParser();